FIG. 1 is a prior art circuit diagram for a lighting system of a motor vehicle. FIG. 1 shows a conventional circuit using a 12 V battery as power supply 1. Lamp 2 represents the load and driver 3 energizes lamp 2. Driver 3 provides a current to lamp 2. Control 4 controls the current to driver 3. This is a typical circuit for use in a dimmer switch of a motor vehicle. In this conventional circuit, the power loss across the driver 3 from a conventional storage battery often is 5 to 10 watts, As a result, expensive drivers with high power capability must be used.